Researchers have found new evidence that vitamin C can significantly reduce levels of oxidative stress (free-radical damage), which is associated with a variety of chronic diseases, for people exposed to environmental tobacco smoke. The study provides hope for people who cannot escape secondhand smoke, whether in the home or at work. The researchers note that cigarette smoke contains large amounts of reactive free radicals, molecules that can cause oxidative damage to cells. Current research links oxidative stress to heart disease, cancer, atherosclerosis, and other chronic diseases.

“It has been well established in test tube studies that vitamin C quenches reactive free radicals from cigarette smoke,” said Marion Dietrich, a UC Berkeley researcher and lead author of the study. “However, there are few studies that have looked at the effects of vitamin C on oxidative stress in secondhand smokers the way we have.”

The researchers looked at 67 adult nonsmokers who were exposed to the smoke of at least one cigarette per day, five days a week, in an indoor setting. They took daily doses of either 500 mg of vitamin C, the vitamin C plus vitamin E and alpha-lipoic acid, or placebo capsules.

The researchers found that after two months of treatment, blood levels of a marker of oxidative damage dropped significantly – by 11.4% and 12.7% for those in the vitamin C and the mixture groups, respectively – compared with those taking the placebo.

“These results are very encouraging,” said Dietrich. “They show that vitamin C may help protect nonsmokers from the oxidative damage caused by secondhand tobacco smoke.”

University of California, Berkeley, Aug 7, 2003